# li = [1,2,3,4]  # [1,3,4]
# # 索引值是奇数的删除
# for i in range(4):
#     if i % 2 == 1:
#         li.pop(i)   # 会报错
# print(li)

# 面试题:
# li = [1,2,3,4,5]   #[1,3,4,5]
# # 索引值是奇数的删除
# for i in range(4):
#     if i % 2 == 1:
#         li.pop(i)   # 结果不对
# print(li)


# li = [1,2,3,4,5]
# for i in range(len(li)-1,-1,-1):
#     if i % 2 == 1:
#         li.pop(i)   # 倒序删除
# print(li)

# 偷换感念
# li = [1,2,3,4,5]
# new_li = []
# for i in range(len(li)):
#     if i % 2 == 1:
#         new_li.append(li[i])
# for em in new_li:
#     li.remove(em)
# print(li)

# li = [1,2,3,4,5]
# for i in range(len(li)-1,-1,-1):
#     if i % 2 == 1:
#         del li[i]   # 倒序删除
# print(li)

# li = [1,2,3,4,5]
# del li[1::2]
# print(li)

# 使用for删除列表的时候从左向右删除,会报错.结果不对

# dic = {"k1":"v1","k2":"v2"}
# for i in dic:
#     dic["k3"] = "v3"
# print(dic)

# 面试题:
# li = [1,2,3,4]
# for i in li:
#     li.append(i)
# print(li)

# 不能在遍历字典本身中改变大小,要批量删除字典的键值对

# dic = {"k1":"v1","k2":"v2","k3":"v3"}
# for i in dic:
#     dic["k7"] = "1"
# print(dic)

# li = []
# for i in dic:
#     if i == "k1" or i == "k3":
#         li.append(i)
# for em in li:
#     dic.pop(em)
# print(dic)

